a) Field of the Invention
The invention is directed to a tear-off safety closure in particular for ensuring authenticity (indicating evidence of tampering) and for additional sealing of a bottle-shaped container containing especially pharmaceuticals which is already closed by a disk-shaped or plug-shaped sealing element. The cap surface and the closed flange-shaped jacket of the closure enclose the sealing element and the rim of the container neck which has an outwardly projecting ridge, this closure having a tear-out part which can be detached from its cap surface, and the jacket has retaining devices which are arranged on its inner surface at a distance from its lower edge and which engage under the lower edge of the ridge.
b) Description of the Related Art
A tear-off closure of the above type is described in DE-OS 27 27 743. It is formed entirely from metal, in particular aluminum. This closure is constructed as a beaded closure, i.e., it covers the sealing element closing the container and covers the neck of the container and engages under the latter in an annular zone located below the rim of the container neck having a ridge. This subsequent deformation, that is, the formation of a bead on the closure, is effected by means of a mechanical device which is arranged downstream in a bottling installation, so that the retaining means which secure the closure on the container are first produced by this mechanical device.
The advantages of such an aluminum closure, i.e., that it can be constructed by cold plastic deformation with suitable tools, that the material itself also has favorable strength and, finally, that common tolerances of the container and the sealing element can be compensated for easily, do not outweigh the disadvantages. One such disadvantage consists in that comparatively heavy mechanical devices for deforming the metallic closures which generate dirt, dust, etc. during operation and are also prone to operating disturbances must be installed in the clean and often sterile filling station for the containers. The sterile environment is also prejudiced by efforts to alleviate the operating disturbances.
A further disadvantage consists in that minute particles are detached from the aluminum alloys used for producing such beaded closures when they come into contact with other objects, especially with the sealing apparatus. This "dust" can very easily contaminate the sealing element and ultimately also the contents of the bottles. Contamination of parenteral preparations with aluminum dust, for example, must be prevented at all costs as this would pose a lethal risk for certain human organs.
But these known aluminum closures have yet a further disadvantage in that they cannot guarantee the authenticity and integrity of the contents of the container. Such metallic closures which are sealed by beading can be opened at the bead and later, again closed, with suitable tools so that the contents could be diluted, for instance, resulting in harmful consequences.
For this reason, one aim of the invention described herein is to provide a tear-off closure which can be produced not from metal, but entirely from thermoplastic in an injection molding process in which it receives its definitive shape, i.e., without having to undergo a final deformation by means of an additional apparatus only after the container to be closed has been filled in order to seal the container completely and safeguard its contents, and this closure is sensitive to tampering so that such tampering can be detected on the closure at any time.
Of course, closures produced from plastic are also already known, e.g., from DE-PS 41 35 470. This reference describes a plastic closing cap, in particular for glass containers used for a wide range of applications, which has a cap surface which can be partially pulled off so as to expose a seal or opening and has a jacket part surrounding the neck of the container. Grippers or spring tongues which are swivelable via predetermined weak points in the material are attached to the jacket part and have grip edges which are directed inward, i.e., toward the outer circumference of the container, and engage under the neck of the container on all sides when swiveled vertically in the closing position. In so doing, the grippers meet and overlap one another in their entirety or individually in a tightly connected manner in the closing position and are accordingly connected in a frictional or positive engagement to form a closed surface surrounding the container neck or are connected in variously divided segments to form such a surface.
This construction of swivelable grippers forming a grip edge and substituting for the beaded edge formed in an aluminum closure by the sealing apparatus is a very complicated form of fastening for such plastic closures. The molding dies used in a plastics injection molding device for producing such closures are themselves very complicated to manufacture. Further, if the closing edge of a container sealed by such a closure is accidentally struck, there is a very high risk that one or more grippers will detach so that a tight closure of the container is no longer ensured.
In order to prevent the detachment of one or more grippers, it is proposed in DE-PS 42 28 090 that an auxiliary cap be screwed over the closure so as to secure the grippers or spring tongues in the radial direction to prevent unwanted opening. Such an additional auxiliary cap also requires that an external thread be arranged on the outer circumference of the closure or on its grippers or spring tongues which renders the overall construction of such a closing device very complicated and difficult to use.
In this known plastic closure and in the closure described in DE-OS 43 07 803, the tear-off cover part of the cap surface is inserted in an opening of the cap surface of the closure having a suitable diameter and engages under the edges of the opening with a clamping lip which projects down in the form of a ring. The circumference of this clamping lip is provided with curved, projecting bulges terminating in the lip of the tear-off cover part. When the tear-off cover part is pulled out of the cap surface by means of the tab provided at this cover part, the frictional forces acting on the lip which is clamped between the sealing element and the underside of the cap surface can cause a loosening of material which is, of course, undesirable since it can lead to contamination.
Moreover, it is obvious that dirt, e.g., dust, etc., can deposit in the circular joint formed between the edges of the tear-off cover part and the edges of the opening in the cap surface of the closure during storage periods and transport periods. When the tear-off cover part is removed to access the contents of the container, this dirt may be distributed on the sealing element located below it and can contaminate the contents of the bottle when this sealing element is pierced by a hypodermic needle.
In other known constructions of plastic closures, these closures are placed over the neck of a bottle-shaped container provided with a sealing element, their cap surface having a circular center part which can be popped out of the cap surface when the closure is pressed down farther toward the container neck, e.g., by exerting a firm thumb pressure. For this purpose, the center part is connected with the outer edge of the cap surface of the closure, e.g., by four thin webs which span a narrow open gap formed between the center part and the edge of the cap surface. This also results in imperfect tightness of the plastic closure in the region of the cap surface, i.e., the sealing element itself is not covered in a sterile manner, but is only protected against unintentional mechanical damage and unwanted puncture prior to actual use of the contents of the bottle.
Therefore, another aim of the invention is to produce the tear-off closure described above in such a way that it is not only formed entirely of plastic but is also formed in one piece and to further develop this tear-off closure in such a way that it can nevertheless be torn off in a manner similar to the closure produced from aluminum and provides protection of the sealing element from contamination.